1. Field of the Invention
The present invention relates to a split type coil separator which is suitable for application into a deflection device of a cathode ray tube apparatus. In more detail, a coil separator which is formed by winding a horizontal deflection coil is constituted as a split type separator, a coupling means is provided at the contact surfaces of a pair of split coil separators and both coil separators are coupled and fixed using this coupling means so that the center axes of both coil separators coupled are perfectly aligned with each other to obtain stabilized deflection characteristic.
2. Description of the Related Art
A deflection device used in a cathode ray tube (CRT) is structured as shown in FIG. 12. In this figure, a funnel type coil separator 12 is provided, as is well known, with a horizontal deflection coil (not illustrated) in its internal circumference surface side and a vertical deflection yoke 14 at its external circumference surface side.
The vertical deflection yoke 14 is also shaped like a funnel and is also provided with the deflection coils at its internal and external circumference surfaces to form as a whole the deflection device 10 for deflecting electron beams in the horizontal and vertical directions.
In the case of using an integrated type structure as shown in the figure as a coil separator 12, a deflection yoke 14 must be inserted onto the external side of this coil separator 12 to form the integrated structure as shown in FIG. 12. For this purpose, the internal diameter of the deflection yoke 14 must be larger than the external diameter of a bending portion 13a provided at the neck portion of the coil separator 12. The bending portion 13a is usually structured with a flange which is sufficiently larger than the internal diameter of the coil separator 12 in order to wind the horizontal deflection coil.
Therefore, if the internal diameter of the deflection yoke 14 is formed matching with the external diameter of the bending portion 13a, when the deflection yoke 14 is loaded to the external circumference surface of the coil separator 12, a considerable gap W is generated against the external circumference surface of the coil separator 12 as shown in the same figure.
When the gap W is large, the vertical deflection efficiency is as much lowered. Therefore, it is required to apply a considerably large vertical deflection current to the vertical deflection coil (not illustrated).
Therefore, the vertical deflection efficiency may be improved by reducing the gap W as much as possible. An example of the related art of the coil separator 12 proposed for this purpose is shown in FIG. 13. Namely, as shown in FIG. 13, the coil separator 12 itself has been formed as the split type coil separator which may be divided into the front and rear portions.
That is, the coil separator 12 is formed of a neck portion side coil separator 12A and a funnel section side coil separator 12B and the vertical deflection yoke 14 to which a vertical deflection coil is wound under the condition that the neck portion side coil separator 12A is isolated is loaded to the external circumference surface of the funnel portion side coil separator 12B.
Since the bending portion 13a is not an obstacle for this loading, the internal surface of the deflection yoke 14 can be formed conforming to the shape of the external circumference surface of the funnel portion side coil separator 12B. Accordingly, a gap W between the coil separator 12B and deflection yoke 14 can be reduced to only a very small value.
Thereafter, the neck portion side coil separator 12A is coupled as shown in FIG. 13 and the horizontal deflection coil is wound to the internal surface of the coil separator 12 under this condition. In view of assuring better loading condition of the vertical deflection yoke 14 for the coil separator 12, the hooks 16a, 16b are formed respectively to the bending portions 13a, 13b for engagement with the deflection yoke in the example of FIG. 13. Thereby, the deflection yoke 14 may be fixed.
Accordingly, since a gap between the coil separator 12 and deflection yoke 14 can be reduced, the deflection efficiency of the vertical deflection coil can be improved remarkably over that of FIG. 12.
Meanwhile, when the coil separator 12 is formed like a split type coil separator, the horizontal deflection coil is generally wound under the condition that the end surfaces of both coil separators 12A, 12B are placed in contact with each other after the deflection yoke 13 is loaded.
Accordingly, when the horizontal deflection coil is wound, the center axis La of the neck portion side coil separator 12A is sometimes not aligned with the center axis Lb of the funnel portion side coil separator 12B and a deviation .DELTA.L is generated due to a coil winding force or holding force of the deflection yoke 14 by means of hooks 16a, 16b.
If such axial deviation .DELTA.L and eccentricity are generated, the predetermined distribution of deflection magnetic field cannot be obtained and in the worst case, it will be required to compensate for the deflection magnetic field. Therefore, careful deflection adjustment work is always required.